Generally, a recent three-dimensional CAD software program that creates a three-dimensional CAD model implements a parametric transformation function, which can transform a dimension of a shape element included in the three-dimensional CAD model as desired by changing the value of a dimensional parameter of the shape element (hereinafter, simply a parameter). Moreover, according to the parametric transformation function, a plurality of parameters can be caused to have a dependence on each other by setting the parameters with a same expression or different expressions using a same variable. In addition, positional relation between shape elements can be used as a parameter.
Furthermore, recent three-dimensional CAD software programs have a function of causing a three-dimensional CAD model to have a program, providing complicated branching conditions by setting the program (hereinafter, referred to as the model built-in program), and setting change logic that associates a changed state, which is a form after transformation, with a condition to be satisfied to shift to the changed state (hereinafter, the function is referred to as a programmed transformation function). According to the function, an expression in which dependence between parameters is set, presence or absence of shape element, or the like, can be changed in accordance with a conditional branch based on a desired parameter, for example.
As a technology relevant to a three-dimensional CAD having the parametric transformation function, there is a technology for improving user operation in visibility by making an input unit for a parameter value into a tabular form (for example, see Patent Document 1 and Patent Document 2). Moreover, there is a technology of enabling a spreadsheet software program to be used as a unit for inputting a parameter by causing the spreadsheet software program and a three-dimensional CAD software program to coordinate (for example, see Patent Document 3).
Patent Document 1: Japanese Patent Application Laid-open No. 2001-338001
Patent Document 2: Japanese Patent Application Laid-open No. 2005-293014
Patent Document 3: Japanese Patent Application Laid-open No. 2005-78207